Niobium is a light gray, crystalline, and ductile transition metal. It has 41 electrons arranged in an electronic configuration of [Kr]4d⁴5s¹. This electron configuration that does not follow Aufbau principle is not unique to niobium.

Discovery

Niobium was recognized by British chemist Charles Hatchett (January 2, 1765 to March 10, 1847) in 1801 (Hatchett,1802a-c). Columbium (symbol Cb) was the name originally given by Hatchett upon his discovery of the metal in 1801. The name reflected that the type specimen of the ore came from the United States of America (Columbia). This name remained in use in American journals—the last paper published by the American Chemical Society with columbium in its title dates from 1953—while niobium was used in Europe.

Major minerals

More than 100 different minerals are known to contain niobium in their crystal structure. Within the elements class a single carbide, niobocarbide ((Nb, Ta)C), is known. Similarly, only a single sulfide, edgarite (FeNb3S6), is known to contain Nb. In the oxide class more than 50 minerals are known with Nb in their structure, for example, aeschynite-(Nd) ((Nd, Ln, Ca)(Ti, Nb)2(O, OH)6), columbite-(Fe) (Fe21Nb2O6), fergusonite-(Y) (YNbO4), hydroxycalciopyrochlore ((Ca, Na, U,)2(Nb, Ti)2O6(OH)), Ixiolite ((Ta, Nb, Sn, Fe, Mn)4O8), lueshite (NaNbO3), polycrase-(Y) (Y(Ti, Nb)2(O, OH)6), and pyrochlore (A2Nb2(O, OH)6Z.

Mining

Large deposits of niobium have been discovered accompanying carbonatites (carbonate-silicate igneous rocks). The three largest currently mined deposits of pyrochlore, two in Brazil and one in Canada were found in the 1950s and are still the main suppliers of niobium mineral concentrates. The largest deposit is found within a carbonatite intrusion in Araxa′, Minas Gerais, Brazil; the other active Brazilian deposit is located near Catala?o, Goia′s, also found within a carbonatite intrusion. Collectively, these two mines yield about 88% of the world's supply. In addition, Brazil has a large but still unexploited deposit near Sa?o Gabriel da Cachoeira, Amazonas, as well as several smaller deposits, notably in the state of Roraima. The third largest supplier of niobium is a carbonatite-hosted mine in Saint-Honore′, near Chicoutimi, Quebec, Canada, which produces between 7% and 10% of the world's supply.

Uses

Niobium is a useful microalloying element for steel, inside which it forms Nb carbide and Nb nitride. These compounds enhance the grain refining and retard recrystallization and precipitation hardening. These effects subsequently improve the toughness, strength, formability, and weldability. Within micro alloyed stainless steels, the Nb concentration is a low(0.1%) but crucial addition to high-strength low-alloy steels that are extensively used structurally in modern vehicles.

Nb is occasionally used in substantially higher amounts for highly wear-resistant machine components and knives. These same Nb alloys are frequently utilized in pipeline construction. Amounts of Nb in Ni-, Co-, and Fe-based superalloys can be as high as 6.5% for specific applications such as jet engine components, gas turbines, rockets, turbocharger systems, heat-resisting, and combustion equipment.